The present invention relates generally to crop harvesting machines and, more particularly, to an infinite reel adjustment mechanism for use in conjunction with a hydraulic reel lifting assembly.
Generally, crop harvesting machines include a crop harvesting header mounted at the forward end thereof to initiate the crop harvesting process. Headers have been developed for utilization in different crops and/or crop conditions. Combines, for example, utilize different crop harvesting headers for soybeans and small grain. Normally, the header operates to cut standing crop material, consolidate it and then convey it rearwardly to the harvesting machine for further harvesting treatment.
Generally, a reel is utilized on the headers to engage standing crop material forward of the cutterbar, pull it rearwardly over the cutterbar, which severs the crop material from the ground, and then convey the severed crop material rearwardly toward the harvesting machine. Often, a consolidating means, such as an auger, is mounted in the header rearwardly of the reel to receive the severed crop material conveyed rearwardly by the reel and consolidate it before feeding rearwardly toward the crop harvesting machine.
It has been found that repositioning the reel relative to the cutterbar, in response to different types and conditions of crop material being harvested, is important to efficient harvesting. For example, efficient harvesting of soybeans necessitates a low positioning of the reel relative to the cutterbar to sweep the crop over the cutterbar and minimize crop loss; however, grain crops normally require a relatively high reel positioning to minimize crop losses. Furthermore, downed crops, where the crops are matted next to the ground, are best harvested by a reel which reaches forwardly of and somewhat below the cutterbar to pick up the downed crop before being severed by the cutterbar.
It is known that grain crops will vary in height above the ground within the same field. To provide for proper reel placement to efficiently harvest such crops of varying sizes, reel assemblies have been equipped with selectively variable reel height controls to selectively vary the height of the reel relative to the cutterbar and, therefore, the ground. One such height control mechanism can be found in U.S. Pat. No. 3,599,410 in the form of hydraulic cylinders mounted between the header frame and the reel arms which are operable to raise and lower the reel.
The hydraulic cylinders are operable within a limited range having a maximum reel height and a minimum reel height relative the cutterbar, with the hydraulic cylinder "bottoming out" at the minimum reel height position. This limited range is generally sufficient to enable the operator to meet the varying conditions found in each crop; however, since reels are also adjustable in a fore-and-aft direction, it is desirable to have the capability of varying the position of the reel when the hydraulic "bottoms out". In this manner, the reel could be moved in a fore-and-aft direction and still be vertically positioned to maintain the proper minimum reel height relative to the cutterbar.
One method for solving this problem was to mount the base of the hydraulic cylinder in a bracket having a series of holes therein so that the operator could selectively vary, within a small finite number, the positions at which the range of the hydraulic cylinder would start; that is, the mounting of the hydraulic cylinder would set the minimum reel height position relative to the cutterbar. This mounting bracket can be seen in the aforementioned U.S. Pat. No. 3,599,410. While this mechanism is practical, it does have the problem of being cumbersome, e.g. difficult to change from one mounting to another, and of being somewhat limited, i.e. setting the minimum reel height position at a location, corresponding to a mounting between the holes in the bracket, wasn't possible. Furthermore, the weight of the reel assembly had to be supported while the hydraulic cylinder was moved from one mounting hole to another, leading to further complications.